The present invention resides in an internal combustion engine with turbo chargers which operate in parallel relationship and of which one includes a charge air duct blocking arrangement with a charge air duct blocking element which can be controllably actuated to block or unblock the charge air duct.
In the state of the art, similar internal combustion engines are known wherein, for an air increase of the engine torque, in particular of charged Diesel engines, a register switching arrangement is used as disclosed for example in the printed publication DE 198 16840C2.
Herein with an increase in the power requirements, a further exhaust gas turbo charger is activated in addition to a base turbo charger. Upon activation of the further exhaust gas turbo charger, it may happen, depending on the engine operating state, that the speed of the accelerated further charger exceeds shortly the speed of the base turbo charger. This may cause a low pressure in the flap valve housing upstream of the further charger running at an excessive speed whereby the air control flap in the charge air supply duct to the further charger is opened. And since the speed of the further charger at this point exceeds the speed of the base charger, the supply air flow via the further charger is, at the same pressure difference, greater than the air supply flow provided by the base charger. With this asymmetric set up, the operating point of the base charger is beyond the pumping limit so that, immediately after the switching procedure, an excessive charger pumping may occur.
Based hereon it is the object of the present invention to provide an internal combustion engine of the type referred to above, which overcomes the disadvantages of the state of the art.